Mouth stick



FIG. 1 is a top, front, side perspective view of a mouth stick showing our new design;

FIG. 2 is an enlarged front end view thereof;

FIG. 3 is a top view thereof;

FIG. 4 is a side view thereof;

FIG. 5 is a bottom view thereof; and,

FIG. 6 is an enlarged rear end view thereof.

The broken lines shown on the mouth stick form no part of the claimed design. 

The ornamental design for a mouth stick, as shown and described. 